Neuro-Oncological Problems in the Intensive Care Unit
Mayur Jayarao
N. Scott Litofsky
I. OVERVIEW: Patients with primary or metastatic tumors may present with the following:
A. Increased intracranial pressure (ICP).
B. Hydrocephalus.
C. Seizures.
D. Postoperative complications.
E. Spinal tumors.
F. Systemic complications secondary to brain tumors.
II. INCREASED ICP
A. Background: Increased volume in a closed intracranial space causes increased pressure (Monro-Kellie doctrine).
B. Pathophysiology.
1. Tumor mass.
2. Hemorrhage.
3. Secondary cerebral edema adjacent to lesion.
4. Hydrocephalus.
5. Hypercarbia.
6. Cerebral ischemia.
C. Diagnosis.
1. Clinical presentation.
a. Headache.
b. Vomiting.
c. Papilledema: chronic finding of ICP elevation.
d. Decreased consciousness.
e. Cognitive changes.
f. Pupillary dilatation.
g. Diplopia.
h. Cushing triad.
i. Systolic hypertension.
ii. Bradycardia.
iii. Respiratory depression.
2. Radiologic studies.
a. Magnetic resonance imaging (MRI): Better resolution than computed tomography (CT).
b. CT: More available than MRI.
D. Treatment of intracranial mass effect and elevated ICP.
1. Head elevation >30 degrees.
2. Fluid restriction (slight).
3. Hyperosmolar therapy (hold if serum osmolality >320 mOsm/kg).
a. Agents.
i. Mannitol 1 to 1.5 g/kg IV bolus initially, then 0.25 to 0.5 g/kg every 4 to 6 hours.
ii. Thirty to fifty milliliters 23.4% NaCl bolus, then 30-mL bolus every 4 to 6 hours.
iii. Three percent hypertonic saline at 30 to 100 mL/h, titrated to a serum sodium goal of approximately 155 mEq/dL.
b. Caveats.
i. Use only one agent at a time.
ii. Close monitoring of renal function and electrolytes.
4. Furosemide 1 mg/kg IV single dose or as 10 to 20 mg adjunct with mannitol.
5. Dexamethasone 10 to 20 mg IV initially, then 4 mg every 6 hours.
6. ICP monitoring (external ventricular drain [ventriculostomy] preferred).
7. Hyperventilation (for short periods only) to achieve PaCO2 25 to 32 mm Hg.
III. HYDROCEPHALUS
A. Background: Increased ventricular size due to increased CSF volume and pressure.
B. Pathophysiology/etiology.
1. Subarachnoid tumor.
a. Leptomeningeal tumor infiltration in subarachnoid space can prevent normal absorption of CSF by arachnoid granulations.
2. Cerebellopontine angle tumors: compress brainstem and fourth ventricle.
3. Intraventricular tumors: obstruct outflow foramen.
4. Intraparenchymal tumors.
a. Basal ganglia and thalamic tumors: compress foramen of Monro.
b. Pineal region tumors: compress third ventricle or cerebral aqueduct.
c. Brainstem or cerebellar tumors: compress fourth ventricle or cerebral aqueduct.
C. Diagnosis.
1. Clinical presentation: Increased ICP (see Section II).
2. Radiologic studies: CT more readily available while MRI demonstrates better detail.
D. Treatment.
1. Dexamethasone 10 to 20 mg IV initially, then 4 mg every 6 hours.
2. External ventricular drain.
3. Tumor resection.
4. CSF diversion either internally (third ventriculostomy) or externally (shunt).
IV. SEIZURES
A. Background: May precipitate rapid deterioration when ICP is elevated.
B. Pathophysiology/etiology.
1. Tumor presence or progression.
2. Hemorrhage.
3. Hypoxia.
4. Hyponatremia.
5. Hypoglycemia.
6. Subtherapeutic anticonvulsant levels.
C. Diagnosis.
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